Rare form of thyroid disease??

I read your article on hypothyroidism. I've been on meds for close to 40
years. My thyroid quit working when I was a teenager. I do not show positive
for hashimotos, so I think I may have one of the other "rare" forms of
thyroid disfunction (possibly related to the pituitary gland??)

Do you have suggestions on a course of action for that, or how to test for it? Over the
last 5 years my thick hair is almost gone - not an exaggeration. Found my T3
was almost nonexistent - switched to 1g of nature thyroid a few months ago
and take 1/4 of a 5mcg Cytomel to boost T3. hair is still falling out. Will
supplements also help if it's one of the rare forms of thyroid disease?